Solenoid operated pressure regulating valve

ABSTRACT

A pressure control device, preferably for use in a control system of an automatic transmission of a motor vehicle, is shown as having a solenoid motor assembly the armature of which, through a cooperating servo orifice, is effective for varying the magnitude of pressure of a fluid medium acting upon a spool slave-like valving member. The spool valving member has at least two cylindrical axially spaced valving portions with one of such valving portions having a diametrical dimension substantially greater than that of the other of the at least two cylindrical axially spaced valving portions.

FIELD OF THE INVENTION

This invention relates generally to pressure control devices forregulating the pressure of a fluid medium and employable, for example,in a control system of an automatic transmission of a motor vehicle.

BACKGROUND OF THE INVENTION

The prior art has proposed pressure control devices, for use in acontrol system of an automatic transmission of an automotive vehicle,and a typical prior art pressure control device is disclosed in U.S.Pat. No. 4,579,145 issued Apr. 1, 1986, with the patentee being HeinzLeiber et al. Said Patent discloses a pressure control device having ahousing which encases an electrically energizable field coil and anarmature. A spool valve carried within a spool valve housing is movabletherein as to control the pressure of a fluid medium passingtherethrough. The spool valve is moved in response to a plunger, and thelike, positioned by the armature so that the plunger, in effect, actsdirectly upon the spool valve and the position and motion of the plungerand spool valve are effectively in unison with the armature.

Various problems and difficulties exist in such prior art devices asdisclosed by said Patent. For example, only relatively low magneticforces are available to cause movement of the spool valve resulting inpoor response time and presenting a potential fouling. As alreadyindicated, the axial position of the spool valve is always dependentupon the position of the armature which, in turn, requires the hydraulicforces to enter into the armature force balance and allows parasiticforces to be transmitted by the spool valve to the armature and such hasa substantial effect on the regulation performed by such prior artdevices. Further, it is somewhat difficult, and significantly costly, tomanufacture such prior art devices because of the need to maintainprecise dimensional relationships, especially axially, between and amongthe armature, spool valve and the cooperating ports controlled by thespool valve.

The foregoing problems, at least to a great extent, have been overcomeby the teachings of U.S. Pat. No. 4,966,195 issued Oct. 30, 1990, withthe patentee being Ralph P. McCabe. However, in some respects thepressure regulator assembly of U.S. Pat. No. 4,966,195 still requiressignificant manufacturing costs as by the use of dual springs atopposite ends of the spool valve and by conveying fluid pressure as fromits output or control pressure chamber, to the functional outer-mostaxial end of the spool valve, as a feed-back pressure.

The invention as herein disclosed and described is primarily directed tothe solution of the foregoing as well as other related and attendantproblems of the prior art.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a pressure regulating assemblyfor regulating the pressure of a flowing fluid medium, comprises housingmeans, said housing means comprising a first housing portion and asecond housing portion, electrical field coil means carried by saidfirst housing portion, pole piece means situated generally within saidfield coil means, a valve seat, fluid-flow passage means formed as to begenerally circumscribed by said valve seat, said pole piece meanscomprising a pole piece end face portion, armature means at least partlysituated generally within said field coil means, said armature meanscomprising an armature end face portion, wherein said armature means issituated with respect to said pole piece means as to thereby cause saidarmature end face portion to be Juxtaposed to said pole piece end faceportion, wherein said second housing portion comprises a generallycylindrical inner chamber, spool valve means situated in saidcylindrical inner chamber and movable with respect to said cylindricalinner chamber and relatively movable with respect to said armaturemeans, said spool valve means comprising at least first and secondaxially aligned cylindrical valving portions, said spool valve meansfurther comprising generally axially extending body means situatedbetween and operatively interconnecting said first and secondcylindrical valving portions, said generally axially extending bodymeans being relatively small in transverse cross-section as to therebydefine an annular chamber circumferentially between said axiallyextending body means and said cylindrical inner chamber and axiallyconfined between said first and second generally cylindrical valvingportions, first fluid inlet passage means formed in said second housingportion as to be generally juxtaposed to said first generallycylindrical valving portion for general control by said first valvingportion, second fluid outlet passage means formed in said second housingportion as to communicate with said annular chamber, third fluid outletpassage means formed in said second housing portion as to be generallyjuxtaposed to said second generally cylindrical valving portion forgeneral control by said second valving portion, fourth fluid passagemeans communicating between said first fluid inlet passage means andsaid fluid-flow passage means, wherein when said armature means is movedas to most restrict flow of said fluid medium out of said fluid-flowpassage means the pressure of said fluid medium causes said spool valvemeans to move in a direction whereby said second valving portion atleast further restricts flow of said fluid medium from said annularchamber and through said third fluid outlet passage means toward sumpand said first valving portion reduces its restrictive effect to flow ofsaid fluid medium through said first fluid inlet passage means and intosaid annular chamber and out of said second fluid outlet passage meansto associated structure to be acted upon by said fluid medium, whereinthe diametrical dimension of said first cylindrical valving portion issubstantially different from the diametrical dimension of said secondcylindrical valving portion, and resilient means normally resilientlyurging said spool valve in a direction generally toward furtherincreasing communication between said annular chamber and said thirdfluid outlet passage means.

Various general and specific objects, advantages and aspects of theinvention will become apparent when reference is made to the followingdetailed description considered in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein for purposes of clarity certain details and/orelements may be omitted from one or more views;

FIG. 1 is a generally axial cross-sectional view of a pressureregulating device employing teachings of the invention; and

FIG. 2 is a generally axial cross-sectional view of another pressureregulating device employing teachings of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring in greater detail to the drawings, FIG. 1 illustrates apressure regulating apparatus or assembly 10 as comprising housing means12 which, in turn, is shown as comprising housing portions or sections14 and 16.

Housing section 14 may be considered as containing, and comprising,electromagnetic motor means 18. The electromagnetic motor means 18 ispreferably comprised of a bobbin 20 having a generally tubular portion22 with outwardly radiating axially spaced flange portions 24 and 26. Anelectrically energizable field coil 28, carried about tubular portion 22and axially contained by and between flanges 24 and 26, has itsconductor ends respectively connected to terminals or contacts 30 and32.

The bobbin 20 is preferably formed of a dielectric plastic material andat its upper flange 24 provided with boss-like portions, one of which istypically shown at 34, which respectively receive and hold the terminals30 and 32. In the preferred embodiment such bosses are integrally formedwith flange 24 in a manner as to be of the same radial distance butangularly spaced from each other.

A preferably dielectric plastic ring-like member 36 has two invertedcup-like portions, one of which is typically shown at 38, whichrespectively receive the two boss-like portions. Each of the invertedcup-like portions is provided with a slot 40 for enabling the passagetherethrough of the respective terminals 30 and 32.

An annular flange-like portion 42 of housing section or body 16 isreceived within and against the inner cylindrical flux return member 44is similarly received by housing body 14 and in axial abutment withflange 42 in a manner whereby a generally outer peripheral portion of adiaphragm 46 is sealingly retained therebetween. The flux return member44 is formed with an axially extending cylindrical passage 48 whichclosely receives an axially extending cylindrical pilot portion 50 ofbobbin 20. As depicted, bobbin 20 is preferably provided with an annularabutment shoulder for engaging an upwardly (as viewed in FIG. 1)directed annular abutment surface or shoulder 52 carried by flux returnring or member 44.

A ring-like or annular wave-type spring 54 is provided as to continuallyresiliently urge flux return member 44 and bobbin 20 in relativelyopposite axial directions.

A cup-like cylindrical armature 56 is slidably received within anaxially extending cylindrical inner surface or passage 58. The lower endof armature 56 is provided as with an axially extending cylindricalportion 60, of relatively reduced diameter, which is depicted asreceiving thereabout the inner peripheral portion of diaphragm 46 whichis retained thereon as by a pressed-on retainer ring.

A generally tubular cylindrical pole piece 62, closely received withincylindrical passage 58, is provided with outer thread means 64 forthreadable engagement with cooperating internal threads 66 of an upperannular or ring-like flux member 68. As typically depicted at 70, theflux member 68 is provided with clearance-like passages or openings forthe reception therein of the inverted cup-like portions one of which istypically shown at 38.

As can be seen, when the opposite end portions 72 and 74 of housing body14 are formed over axially outer surfaces of upper flux ring 68 andflange portion 42 of housing body 16, the inner annular shoulder orabutment surface 76 of upper flux ring 68 is urged against bobbin body20 (in the direction of flange portion 42) while the flange 42, throughlower flux ring 44 and its shoulder or abutment surface 52, urges bobbin20 in the opposite axial direction (generally toward upper flux ring 68)thereby containing such members or elements in axially assembledcondition. If for some reason less than a totally axially abuttingcondition should occur, the wave spring 54 serves to assure that norelative axial movement will occur during operation as between and/oramong flange 42, flux ring 44, bobbin 20 and upper flux ring 68 (andpole piece 62 threadably engaged with flux ring 68).

A combination flow member and adjustable spring seat member 80 isreceived within both a passage or chamber 78 of armature 56 and passage82 of pole piece 62. Preferably, member 80 is closely piloted withinpassage 82, as by a coacting outer cylindrical portion, and providedwith an externally threaded portion 84 coacting with an internallythreaded portion 86 of pole piece member 62. In the preferredembodiment, adjustable member 80 is formed of non-magnetic stainlesssteel.

The lower end (as viewed in FIG. 1) of adjustment member 80 is providedwith an axially extending pilot-like portion and an annular shoulderthereabout for operatively piloting and engaging the upper end ofresilient means 88, such as a coiled compression spring, the lower endof which operatively engages an inner axial end wall or shoulder ofpassage or chamber 78 as to thereby resiliently urge armature means 56in a downward direction as viewed in FIG. 1.

An axially extending portion of adjustment member 80 is preferably madeto provide for a controlled clearance with respect to the cylindricalinner surface of chamber 78. More particularly, in one embodiment of thepressure regulating apparatus 10, the total specified diametricalclearance as between the outer cylindrical portion 90, of member 88, andthe juxtaposed inner cylindrical surface of chamber or passage means 78,ranged from 0.37 mm. to 0.49 mm. with the difference therebetween beingallowable dimensional tolerance.

The upper end of adjustment means 80 is provided with socket-liketool-engaging surface means 92, whereby member 80 may be threadablyaxially adjusted relative to pole piece 62, while the tool-engagingsurface means for pole piece 62, preferably, take the form of aplurality of recesses 94--94 in the upper axial end thereof as to enablethe engagement therewith of a spanner wrench, or the like, for thethreadable axial adjustment of pole piece 62 relative to flux pathmember 68. Adjustment means 80 is also provided with transverse passageor conduit means 96 which serve to communicate as between the generallyannular space, between pole piece end face means 98 and opposed armatureend face means 100, and axially extending passage or conduit means 102.In the preferred embodiment, a ring-like or annular spacer 104 issituated in the space between opposed end faces 98 and 100 of pole piece62 and armature 56, respectively. Further, in the preferred embodiment,the spacer 104 is formed of non-magnetic material as, for example,half-hard brass.

The lower axial end (as viewed in FIG. 1) of armature means 56 haspassage or conduit means 106 formed therethrough as to, generally,communicate from an area axially outwardly of extension 60 to thepassage or chamber means 78 of armature 56. Fluid flow restriction means108, having calibrated flow passage means 110, is situated as in conduitmeans 106 to thereby provide for a restricted flow of fluid therethroughand into chamber or passage means 78.

Housing section or portion 16 is illustrated as comprising a housingbody 112, of which flange portion 42 preferably comprises an integralportion, having an outer cylindrical surface 114 operatively received asin an inner cylindrical surface 116 of associated support structure 118carried as by an automotive power transmission means 120. Asillustrated, the body 112, of non-magnetic material, may have suitableflange means 122 by which the body 112 can be suitably secured tostructure 118.

A spool valve member 124, preferably of aluminum alloy, having axiallyspaced first and second generally tubular valve portions 125 and 127with outer cylindrical surfaces 126 and 128 respectively carriedthereby, is slidably received within a cooperating passage comprising atleast a first axially extending cylindrical surface 130 and a secondrelatively smaller axially extending cylindrical surface 132 which maybe considered as being in communication with each other. As shown, valvebody portion 125 is closely slidably received within passage portion 130while valve body portion 127 is closely slidably received within passageportion 132.

Valve body portions 125 and 127 are joined to each other by an axiallyextending intermediate body portion 134. Preferably, body portion 134has a cylindrical outer surface of generally reduced diameter, ordiameters, thereby forming, in combination with passages 130 and 132,annular chamber or passage means 136. Spool valve member 124 is providedwith axially extending passage or conduit means 138 effectivelycommunicating with a recess or cavity 140, formed axially into valvebody portion 125, and a calibrated flow restriction 142 whichcommunicates, as through a conduit portion 144, with an annularcircumferentially formed recess or groove 146.

In the preferred embodiment, a generally cylindrical valve seat orpoppet valve seat member 148, preferably of non-magnetic stainlesssteel, is sealingly pressed into a recess 150 in valve housing or body112. In the embodiment shown, a chamber 152 is formed as to be axiallyof valve body portion 125 and larger in diameter than the outercylindrical surface 126 of valve body portion 125. A passage or aperture154, generally centrally formed through valve seat member 148,communicates with chamber or cavity 152 and cavity 140. When theapparatus 10 is in a condition wherein the armature 56 is in itsdown-most position (as viewed in FIG. 1), an annular valving surface156, formed generally circumferentially about passage or conduit means106 and carried by armature means 56, sealingly abuts against acooperating valve seating surface 158 of valve seat means 148.

A chamber 160 is formed generally between diaphragm means 46 and theflange (42) end of housing section means 16. A plurality of apertures orpassages 162, formed in housing section 16, serve to communicate betweenchamber 160 and an area relatively low reference or sump pressure,P_(s). For purposes of disclosure, it may be assumed that the apparatus10 and related cooperating support structure 118 are situated as to begenerally surrounded by a relatively low reference, or sump, fluidpressure P_(s).

A first recess or groove 164 is formed circumferentially into the outersurface 114 of housing portion 112 while a second recess or groove 166is formed circumferentially into inner passage 132. A plurality ofgenerally radially extending passages or conduits 168 serve to completecommunication between recesses or grooves 164 and 166. A relatively highpressure source or supply means 170, for supplying a fluid at arelatively high pressure, is in communication with annular groove orflow path 146 as via inner annular groove 166, conduit means 168,annular groove or recess 164 and conduit or passage means 172.

Similarly, an annular groove or recess 174 is formed generallyperipherally into the outer surface 114 and is placed into communicationwith inner space or chamber means 136 as by a plurality of conduits orapertures 176. A control means 178 to be acted upon by fluid pressure,regulated or determined by valving means 124, is in communication withchamber 136, conduits or passages 176 and recess or flow ring 174 as viaconduit or passage means 180.

A further annular groove or recess 812 is formed generally peripherallyinto the inner surface 130, of housing body 112, and placed intocommunication with said area of sump pressure as by conduit or passagemeans 184.

In the preferred embodiment, an end cap member 186, of generallydisc-like configuration, is retained as within a bore formed in thelower end (as viewed in FIG. 1) of housing section or body 112. Anaperture or passage 188, formed through end cap member 186, completescommunication as between the fluid of low or sump pressure and conduitportion 132 axially beyond the outer end of valving body 127.

in the embodiment of FIG. 1, a resilient means such as, for example, acoiled compression spring 190 is situated in the control chamber means136 and normally resiliently urges the spool valve 124 upwardly (asviewed in FIG. 1) or toward poppet valve seat member 148.

OPERATION OF EMBODIMENT OF FIG. 1

Generally, the pressure regulating valving assembly 10, controls and/ordetermines fluid output pressure in response to an electrical current,as by returning a portion of such fluid to, for example, sump. Moreparticularly, an electrical signal, in which the magnitude of thecurrent may be an indication of a sensed condition or an indication ofthe then desired operation of the control means 178, is applied to thefield winding 28, as by terminals 30 and 32. This, in turn, creates amagnetic field with the path of the resulting flux being generallyaxially through pole piece 62, through flux ring or member 68, throughhousing section 14, through flux member 44, generally axially alongarmature means 56 and back to pole piece means. The calibrated springmeans 88 resiliently resists the movement of armature means 56 away fromvalve seat member 148; however, generally, the greater the magnitude ofthe electrical current applied to the field coil means 28 the furtherwill armature means 56 move, away from valve seat member 148, againstthe resilient resistance of spring means 88. In the preferred form ofthe embodiment of FIG. 1, the spring means 88 is adjusted, viaadjustment means 80, as to apply an initial biasing force tending tomaintain armature means 56 seated against valve seat member 148, therebyrequiring a corresponding or related predetermined magnitude ofelectrical current to be first applied to field coil means 28 before thearmature means 56 undergoes any opening movement with respect to valveseat member 148.

For ease of disclosure and understanding, the magnitude of the pressureof fluid provided by supply means 170 may be considered as being ofconstant relatively high magnitude, P₁. Assuming that armature means 56is held against valve seat member 148, it can be seen that fluid at asupply pressure P₁ will flow into recess or groove 146, through conduit144 and calibrated flow restriction 142, into passage or conduit means138, into chamber or cavity 140 and into the chamber means 152. Some ofsuch fluid flows into passages or conduits 154 and 106 with a smallportion flowing through calibrated passage 110 of restriction means 108.As a consequence, the magnitude of fluid pressure in chamber 152, cavityor chamber 140, and conduits or passages 138 is at its maximum while theopposite end, valve body portion 127, is exposed to the low sumppressure P_(s). This, in turn causes the spool valve member 124 toaxially move a maximum distance, against the resistance of spring means190, thereby assuredly terminating communication as between controlchamber 136 and conduit means 184 while, simultaneously, openingcommunication as between recess means 166 and control chamber 136. Themagnitude of the fluid pressure within control chamber 136 increases toits maximum value causing P_(c) to approach the value of P₁.

The various clearance in the electromagnetic motor means 18 are filledwith fluid. In order to continually assure that all air is purged, fluidis flowed through calibrated restriction passage means 110 and into thechamber within armature means 56.

As was previously described, there is a calculated, very small annularpassage between the outer surface of cylindrical portion 90 and thejuxtaposed portion of spaced inner cylindrical surface 78. Therestrictive effect thereof, to flow of fluid therethrough, is such as topreferably provide a rate of flow just slightly less than the rate offlow through said calibrated restrictive passage means 110. The fluidflowing through the tubular-like flow passage, between 90 and 78, flowsinto the annular space generally between opposed faces 98 and 100 andflows into the space between the outer cylindrical surface of armaturemeans 56 and the juxtaposed inner cylindrical surface 58 of bobbin means20. Because of the movement which armature means 56 undergoes, relativeto bobbin means 20, the fluid therebetween generally circulates andeventually flows to sump as via radial passage means 96 and axialpassage means 102, as well as the tool engaging socket 92. Suchcirculation of fluid results in the continuing assurance that anypockets of air, which may occur, are purged to sump.

When the magnitude of the electrical current applied to the field coilmeans 28 becomes sufficient to have the magnetic force of the generatedflux overcome the pre-load of spring means 88, the armature 56 willstart to move toward pole piece means 62 and as this occurs, the valvingend surface 156 moves away from valve seating surface 158 of valve seatmember 148. The magnitude of the electrical current necessary to thuslyovercome the pre-load of spring 88 may be considered to be a"threshhold" value or magnitude of current. As should now be evident,the greater the magnitude of the current, the more armature means 56moves away from valve seat member 148 and toward pole piece means 62. Asthe armature means 56 undergoes such motion, fluid flows out of passagemeans 154, between spaced surfaces 156 and 158 and into chamber 160which is at or very close to sump pressure, P_(s). Such fluid is thenable to pass through conduit means 162--162. As a consequence, themagnitude of the pressure of fluid in chamber 152, chamber or cavity140, and passages 138 decreases because of the restriction 142 and therelatively less restricted flow out of passage 154. This, in turn,enables the magnitude of the pressure of fluid in chamber 136 to workagainst the spool valve 124 in conjunction with the biasing resilientmeans 190 to move spool valve 124 upwardly (as viewed in FIG. 1) openingor further increasing communication as between control pressure chamber136 and bypass-like passage means 182, 184 to sump, while communicationas between annulus 166 and control chamber 136 is being reduced by thecylindrical surface 128.

EMBODIMENT OF FIG. 2

In FIG. 2 all elements and/or details which are like or similar to thoseof FIG. 1 are identified with like reference numbers provided with asuffix "a".

Referring in greater detail to FIG. 2, the electromagnetic motor means18a, in addition to the elements thereof which are identified as beinglike or similar to those of FIG. 1, comprises a generally annular orring-like flux member 268 which is preferably piloted on and about acylindrical pilot portion or extension 200 of bobbin 20a.

The flange portion 42a is in axially abutting condition with a fluxmember 44a, which also comprises pole piece means 202 pilotinglyreceived in the lower (as viewed in FIG. 2) end of the tubularcylindrical body portion 22a as to have the inner cylindrical surface58a preferably closely received about the pole piece means 202.

A generally cylindrical armature 204 has its upper end (as viewed n FIG.2) of a generally cup-shaped configuration wherein the inner cylindricalwall 206 is closely received about and axially slidable relative to adepending generally cylindrical portion 208. In one embodiment of thestructure of FIG. 2, it was determined that a diametrical clearance,between the outer cylindrical surface 210, of portion 208, and the innercylindrical surface 206 of armature 204 could be from 0.19 mm. to 0.29mm. with the difference therebetween being permissible dimensionaltolerances.

The generally tubular depending portion 208 is preferably formedintegrally with a generally transversely extending end plate member 212which is preferably formed of non-magnetic stainless steel and providedwith suitable openings for respectively accommodating the boss-likeportions one of which is typically shown at 38a.

An annular flange-like portion 42a of housing section or body 16a isreceived within and against the inner cylindrical surface of housingsection or body 14a. The flux member 44a is similarly received byhousing or body 14a and is in axial abutment with flange portion 42a ina manner whereby a generally outer peripheral portion of a diaphragm 46ais sealingly retained therebetween.

When the elements are assembled and the ends 72a and 74a of outerhousing section or body 14a are formed over as depicted, flux washer 268presses axially downwardly (as viewed in FIG. 2) against bobbin flange24a, causing the lower disposed annular surface of bobbin 20 to bearagainst a juxtaposed annular abutment surface or shoulder 52a carried bythe flux member 44a and consequently having the flux member 44a abutagainst body flange 42a and in so doing retaining the outer peripheralportion of diaphragm means 46a therebetween.

In the preferred embodiment of the structure of FIG. 2, an axialadjustment member 214 is provided in cooperation with armature means204. More particularly, armature means 204 has a cylindrical passage orbore 216, formed centrally and axially thereof, and which receives theadjustment member 214 therein as by a press-fit between bore 216 andouter cylindrical surface 218 of member 214. In assembling adjustmentmember 214 and armature 204, the armature 204 is pressed onto member 214until the desired working gap, as between pole piece end face means 220and armature end face means 222, is achieved, such, of course, beingpossible to establish in terms of the axial distance of valve seatingsurface 156a to the armature end face means 222.

Cylindrical portion 208 is provided with an inlet aperture or passage224 leading as to a cylindrical chamber 226 which has a seat-likesurface 228 depicted as being generally conical. An adjustable member230, having an axial end 232 effective for cooperating with seat-likesurface 228, is threadably engaged with portion 208 to thereby enablethe selective adjustment of end 232 relative to conical surface 228 asto achieve a desired restricted rate of fluid flow therebetween and intothe remainder of cylindrical chamber 226. Member 230 has passage orconduit means 234 formed generally transversely and opening, at bothends, into cylindrical chamber 226. An axially extending conduit orpassage 236 serves to communicate between conduit means 234 and asocket-like tool-engaging surface means 238 thereby being incommunication with sump pressure, P_(s).

In the preferred form of the embodiment of FIG. 2, axially extendingadjustment member 214, extension 208, adjustment member 230 and endmember 212 are all formed of non-magnetic material. Preferably, members212, 214 and 230 are of non-magnetic stainless steel, while the spoolvalve 124a and housing 16a are of aluminum alloy.

A visual inspection of both FIGS. 1 and 2 will show that the details andelements comprising the spool valve, spool valve housing or body and thevarious conduits, passages, porting and apertures are functionally thesame.

That is, the valving assembly preferably employs a poppet orifice 154a(154), in series with a fluid feed or supply restriction 142a (142), tovary a pressure which acts directly on the spool valve 124a (124). Aregulating poppet valve 156a (156) is employed to vary the magnitude ofthe fluid pressure at the poppet orifice means 154a (154).

As already indicated, the poppet regulating valve 156a (156) may, infact, be positioned some small distance, for example 0.005 inch, awayfrom the poppet valve seat surface 158a (158) and, depending upon suchdistance, fluid flow is restricted across seating surface means 158a(158) which, in turn, creates a back pressure at poppet orifice means154a (154) with such back pressure being transmitted to chamber 152a(152), cavity or passage means 140a (140) and passage means 138a (138)of spool valve 124a (124).

Fluid at a supply pressure, P₁ is fed as through conduit means 172a(172), through annulus 164a (164), conduit means 168a (168), annulus146a (146), and, through calibrated restriction means 142a (142) tospool valve 124a (124) passage and/or chamber means 138a (138) and 140a(140). As the magnitude of the fluid pressure within 138a (138), 140a(140) and 152a (152) thusly increases, the spool valve 124a (124)experiences an increasing axially directed force which is in a directionopposed to by the magnitude of the pressure of fluid in chamber 136a(136) and the spring means 190a (190).

When such a hydraulic force axially against spool valve 124a (124)becomes sufficient to overcome the force of spring 190a (190), the spoolvalve 124a (124) will begin to move axially away from poppet valve seatmember 148a (148) and toward end cap member 186a (186) and exhaust portor passage 188a (188). Such movement by spool valve 124a (124), towardexhaust port 188a (188), causes the supply port regulating surface 113a(113), which comprises a portion of the outer cylindrical surface 128a(128), to effectively decrease thereby allowing more fluid, at P₁, toflow out of annulus 166a (166) and into control chamber 136a (136).Simultaneously, as regulating surface 113a (113) is thusly decreasing,the exhaust port regulating surface 115a (115), which comprises aportion of the outer cylindrical surface 126a (126), increases andincreasingly restricts fluid flow out of control chamber 136a (136) andinto annulus 182a (182) and exhaust passage or conduit means 184a--184a(184--184) to sump. The combination of the extra flow of fluid intocontrol chamber 136a (136) and the reduction of fluid flow out ofcontrol chamber 136a (136) and into exhaust passage means 184a --184a(184--184) will create a magnitude of control pressure within controlchamber 136a (136) which will act upon the spool valve 124a (124) andbring the spool valve 124a to a condition of rest with the varioushydraulic forces and spring force being in equilibrium.

The difference in the diametrical dimensions of spool valve cylindricalportions 126a (126) and 128a (128) enables the spool valve 124a (124) toachieve a state of equilibrium with a magnitude of fluid pressure incontrol chamber 136a (136) greater than the then magnitude of fluidpressure in cavities or chambers 152a (152), 140a (140) and 138a (138).

In the embodiments of FIGS. 1 and 2, the spool spring means 190a (190)is capable of providing a balancing force to maintain a zero pressure inthe control chamber 136a (136) when the inner chamber means 138a, 140aand 152a (138, 140 and 152), and thus poppet orifice means 154a (154),still have a positive fluid pressure therein.

Further, the invention, through the use of different diameters ofcylindrical portions 126a (126) and 128a (128) enables the control portor passage means 176a (176) to have the fluid therein be at a value ormagnitude equal to 100.0% of supply pressure, P₁, without requiring thepressure of the fluid within chamber means 140a (140) and 138a (138) tobe at a magnitude of 100.0% of supply pressure, P₁. It has also beendetermined that good operating characteristics are obtained when theratio of the diametrical dimensions of the outer cylindrical surfaces126 and 128 are within a range of ratios of 1.1 to 1.5; that is, theouter diametrical dimension of cylindrical surface 126, divided by theouter diametrical dimension of cylindrical surface 128 would be in therange of values ob 1.1 to 1.5. The same applies to cylindrical surfacesor portions 126a and 128a. In the preferred embodiments the ratio of thediametrical dimensions of cylindrical surface 126 to cylindrical surface128, and, cylindrical surface 126a to cylindrical surface 128a was, ineach case, selected to be in the order of 1.3.

Still further, referring to either FIGS. 1 or 2, let it be assumed thatvarious valves and/or flow devices are in parallel branch circuit withrespect to the depicted control means 178 or 178a. If for some reasonone or more of such assumed valves and/or flow devices were to open in amanner causing the magnitude of P_(c) to, undesirably, decrease, theinvention will automatically correct for such decrease. For example,referring to FIG. 1, if P_(c) in conduit 180 were to start diminishingin magnitude, the fluid in the control chamber 136 would also diminishin pressure; this would then cause spool valve 124 to become unbalancedand move downwardly, as viewed in FIG. 1, causing the regulating surface115 to move in a direction of further closing flow from control chamber136 to exhaust conduit means 184--184, and causing regulating surface113 to move in a direction of further increasing the flow and pressureof fluid from annulus 166 to control chamber 136. Such action wouldcontinue until P_(c) was again at desired magnitude and spool valve 124again achieved equilibrium. The same automatic correction, as described,would of course occur in the embodiment of FIG. 2.

The operation of the pressure regulating valving assembly 10a of FIG. 2is generally similar to the embodiment of FIG. 1.

Generally, the pressure regulating valving assembly 10a controls and/ordetermines fluid output pressure, in response to an electrical current,as by returning a portion of such fluid to, for example, sump. Moreparticularly, an electrical signal, in which the magnitude of thecurrent may be an indication of a sensed condition or an indication ofthe then desired operation of the control means 178a is applied to thefield winding 28a as by terminals 30a and 32a. This, in turn, creates amagnetic field with the path of the resulting flux being generallyaxially through pole piece 202, through flux ring portion 44a, throughhousing section 14a, through flux member 268, generally axially alongarmature means 204 and back to pole piece means 202.

The embodiment of FIG. 2 does not need to employ spring means such as at88 of FIG. 1. That is, the regulating apparatus or device 10a of FIG. 2has an aspect which is opposite to that of FIG. 1. More particularly,device 10 is one which contemplates that at zero or low magnitude ofelectrical input to field coil 28, spring 88 will maintain valvingsurfaces 156 and 158 effectively closed which, in turn, causes P_(c) tobe equal, or almost equal to P₁. Such a device 10 may be considered asbeing one wherein, normally, the output of which, as at 180, is "high".

In comparison, the apparatus or device 10a contemplates that: (a) thecurrent flow through field coil means 28a will be opposite to that incoil means 28 and (b) upon application of a signal type current flowthrough field coil means 28a, armature means 204, member 214 and valvesurface 156a will be urged toward seat member 148a and spool valve 124a.

Assuming that supply means 170a is supplying fluid at a pressure of P₁and assuming that either a zero or low magnitude of current is suppliedto coil means 28a, the supply fluid will pass through restriction 142a,through chamber means or passages 138a, 140a and 152a and, by its actionagainst restriction means 108a, cause the armature means 204, member 214and valving member surface 156a to move its furthermost distance awayfrom valve seating surface 158a and spool valve means 124a.Consequently, the supply fluid flows, at a comparatively large rate offlow, between the cooperating spaced surfaces 156a and 158a and to sumpas via 160a and conduits 162a--162a. Such flow between spaced surfaces156a and 158a causes the magnitude of the pressure of the fluid in 138a,140a and 152a to decrease (also due to the pressure drop acrossrestriction 142a) thereby enabling spring 190a to move spool valve 124agenerally upwardly (as viewed in FIG. 2) causing the regulating surfaceportion 113a to further reduce flow, from annulus 166a to controlchamber 136a, and simultaneously causing the regulating surface portion115a to further increase flow, from control chamber 136a to annulus 182aand sump via passages 184a. This results in the fluid in control chamber136a being at or near its lowest permissible magnitude and such isconveyed as an output pressure to control means 178a.

The embodiment of FIG. 2 may be considered as a pressure regulatingdevice which normally has a low pressure output.

As the magnitude of the current applied to field coil 28a increases, theresulting flux becomes sufficient to (in response to the magnitude ofthe applied current) cause the armature means 204 and valve surface 156ato move toward valve seating surface 158a. As a consequence therestrictive effect of the then closer spaced surfaces 156a and 158aincreases causing the magnitude of the supplied fluid in chambers 138a,140a and 152a to increase. Such, in turn, moves spool valve 124agenerally away from valve seating surface 158a resulting in regulatingsurface 113a permitting an increase in flow from annulus 166a andsimultaneously resulting in regulating surface 115a causing a reductionin flow from control chamber means 136a to sump via annulus 182a andconduit means 184a.

As in the embodiment of FIG. 1, so too, restriction means 108a andrestriction passage means 110a permit a relatively small rate of flow offluid into and through passage or conduit means 106a as to fill chamber206 as well as other available space (for example, between elementsrelatively movable to each other). An outflow restriction means,comprised of extension 208, member 230 and cooperating surfaces 228 and232, serves to control the rate of flow of fluid therethrough and, viaconduit or passage means 224, 226, 234, 236 and 238, to sump. The member230 is adjusted as to present juxtaposed surfaces 228 and 232 to eachother at a distance (or space therebetween) which will result in thedesired rate of fluid flow therethrough. In the preferred embodiment,the rate of flow of fluid through such outflow restriction means isslightly less than the rate of flow through restriction passage means110a. The purpose of restriction passage means 110a and the outflowrestriction means is the same as already described in regard to 110,90-78, 96, 102 and 92 of FIG. 1.

Further, as should now be apparent, the spool valve 124 (124a)accomplishes its overall regulating function without supplying afeed-back of fluid pressure as from control chamber means 136 (136a) tothe functional outer axial end of valving body portion 127 (127a) ofspool valve 124 (124a), a taught by said U.S. Pat. No. 4,966,195.

Also, by preferably placing the spring 190 (190a), about spool valve 124(124a), so that said spring is located effectively between opposed axialends of spool valve 124, the overall length of the device or apparatus10 (10a) can be minimized as compared to, for example, said U.S. Pat.No. 4,966,195.

Although only preferred embodiments of the invention have been disclosedand described it is apparent that other embodiments and modifications ofthe invention are possible within the scope of the appended claims.

What is claimed is:
 1. A pressure regulating assembly for regulating thepressure of a flowing fluid medium, comprising housing means, saidhousing means comprising a first housing portion and housing a secondhousing portion, electrical field coil means carried by said firsthousing portion, pole piece means situated generally within said fieldcoil means, a valve seat, fluid-flow passage means formed as to begenerally circumscribed by said valve seat, said pole piece meanscomprising a pole piece end face portion, armature means at least partlysituated generally within said field coil means, said armature meanscomprising an armature end face portion, wherein said armature means issituated with respect to said pole piece means as to thereby cause saidarmature end face portion to be juxtaposed to said pole piece end faceportion, wherein said second housing portion comprises a generallycylindrical inner chamber, spool valve means situated in saidcylindrical inner chamber and movable with respect to said cylindricalinner chamber and relatively movable with respect to said armaturemeans, said spool valve means comprising at least first and secondaxially aligned cylindrical valving portions, said spool valve meansfurther comprising generally axially extending body means situatedbetween and operatively interconnecting said first and secondcylindrical valving portions, said generally axially extending bodymeans being relatively small in transverse cross-section as to therebydefine an annular chamber circumferentially between said axiallyextending body means and said cylindrical inner chamber and axiallyconfined between said first and second generally cylindrical valvingportions, first fluid inlet passage means formed in said second housingportion as to be generally juxtaposed to said first generallycylindrical valving portion for general control by said first valvingportion, second fluid outlet passage means formed in said second housingportion as to communicate with said annular chamber, third fluid outletpassage means formed in said second housing portion as to be generallyjuxtaposed to said second generally cylindrical valving portion forgeneral control by said second valving portion, fourth fluid passagemeans communicating between said first fluid inlet passage means andsaid fluid-flow passage means, wherein when said armature means is movedas to most restrict flow of said fluid medium out of said fluid-flowpassage means the pressure of said fluid medium causes said spool valvemeans to move in a direction whereby said second valving portion atleast further restricts flow of said fluid medium from said annularchamber and through said third fluid outlet passage means toward sumpand said first valving portion reduces its restrictive effect to flow ofsaid fluid medium through said first fluid inlet passage means and intosaid annular chamber and out of said second fluid outlet passage meansto associated structure to be acted upon by said fluid medium, whereinthe diametrical dimension of said first cylindrical valving portion issubstantially different from the diametrical dimension of said secondcylindrical valving portion, and resilient means normally resilientlyurging said spool valve means in a direction generally toward furtherincreasing communication between said annular chamber and said thirdfluid outlet passage means, wherein said diametrical dimension of saidsecond cylindrical valving portion is substantially larger than saiddiametrical dimension of said first cylindrical valving portion, whereinsaid resilient means comprises mechanical spring means, and wherein saidspring means is situated generally within said annular chamber.
 2. Apressure regulating assembly for regulating the pressure of a flowingfluid medium, comprising housing means, said housing means comprising afirst housing portion and a second housing portion, electrical fieldcoil means carried by said first housing portion, pole piece meanssituated generally within said field coil means, a valve seat,fluid-flow passage means formed as to be generally circumscribed by saidvalve seat, said pole piece means comprising a pole piece end faceportion, armature means at least partly situated generally within saidfield coil means, said armature means comprising an armature end faceportion, wherein said armature means is situated with respect to saidpole piece means as to thereby cause said armature end face portion tobe juxtaposed to said pole piece end face portion, wherein said secondhousing portion comprises a generally cylindrical inner chamber, spoolvalve means situated in said cylindrical inner chamber and movable withrespect to said cylindrical inner chamber and relatively movable withrespect to said armature means, said spool valve means comprising atleast first and second axially aligned cylindrical valving portions,said spool valve means further comprising generally axially extendingbody means situated between and operatively interconnecting said firstand second cylindrical valving portions, said generally axiallyextending body means being relatively small in transverse cross-sectionas to thereby define an annular chamber circumferentially between saidaxially extending body means and said cylindrical inner chamber andaxially confined between said first and second generally cylindricalvalving portions, first fluid inlet passage means formed in said secondhousing portion as to be generally juxtaposed to said first generallycylindrical valving portion for general control by said first valvingportion, second fluid outlet passage means formed in said second housingportion as to communicate with said annular chamber, third fluid outletpassage means formed in said second housing portion as to be generallyjuxtaposed to said second generally cylindrical valving portion forgeneral control by said second valving portion, fourth fluid passagemeans communicating between said first fluid inlet passage means andsaid fluid-flow passage means, wherein when said armature means is movedas to most restrict flow of said fluid medium out of said fluid-flowpassage means the pressure of said fluid medium causes said spool valvemeans to move in a direction whereby said second valving portion atleast further restricts flow of said fluid medium from said annularchamber and through said third fluid outlet passage means toward sumpand said first valving portion reduces its restrictive effect to flow ofsaid fluid medium through said first fluid inlet passage means and intosaid annular chamber and out of said second fluid outlet passage meansto associated structure to be acted upon by said fluid medium, whereinthe diametrical dimension of said first cylindrical valving portion issubstantially different from the diametrical dimension of said secondcylindrical valving portion, and resilient means normally resilientlyurging said spool valve means in a direction generally toward furtherincreasing communication between said annular chamber and said thirdfluid outlet passage means, wherein said resilient means comprisesmechanical spring means, and wherein said spring means is situatedgenerally within said annular chamber.
 3. A pressure regulating assemblyaccording to claim 2 wherein said cylindrical inner chamber comprises afirst inner cylindrical surface of a first diametrical dimension and asecond inner cylindrical surface of a second diametrical dimensionsubstantially different from said first diametrical dimension, whereinsaid second diametrical dimension is substantially larger than saidfirst diametrical dimension, and wherein said first and secondcylindrical valving portions are respectively received by said first andsecond inner cylindrical surfaces.
 4. A pressure regulating assemblyaccording to claim 2 wherein said field coil means is effective forproducing a magnetic flux upon application of an electrical current tosaid field coil means, and wherein when a preselected magnitude ofelectrical current is flowed through said field coil means said armaturemeans is moved as to most restrict flow of said fluid medium out of saidfluid-flow passage means.
 5. A pressure regulating assembly according toclaim 2 wherein said field coil means is effective for producing amagnetic flux upon application of an electrical current to said fieldcoil means, and wherein when a preselected magnitude of electricalcurrent is flowed through said field coil means said armature means ismoved as to least restrict flow of said fluid medium out of saidfluid-flow passage means.
 6. A pressure regulating assembly forregulating the pressure of a flowing fluid medium, comprising housingmeans, said housing means comprising a first housing portion and asecond housing portion, electrical field coil means carried by saidfirst housing portion, pole piece means situated generally within saidfield coil means, a valve seat, fluid-flow passage means formed as to begenerally circumscribed by said valve seat, said pole piece meanscomprising a pole piece end face portion, armature means at least partlysituated generally within said field coil means, said armature meanscomprising an armature end face portion, wherein said armature means issituated with respect to said pole piece means as to thereby cause saidarmature end face portion to be juxtaposed to said pole piece end faceportion, wherein said second housing portion comprises a generallycylindrical inner chamber, spool valve means situated in saidcylindrical inner chamber and movable with respect to said cylindricalinner chamber and relatively movable with respect to said armaturemeans, said spool valve means comprising at least first and secondaxially aligned cylindrical valving portions, said spool valve meansfurther comprising generally axially extending body means situatedbetween and operatively interconnecting said first and secondcylindrical valving portions, said generally axially extending bodymeans being relatively small in transverse cross-section as to therebydefine an annular chamber circumferentially between said axiallyextending body means and said cylindrical inner chamber and axiallyconfined between said first and second generally cylindrical valvingportions, first fluid inlet passage means formed in said second housingportion as to be generally juxtaposed to said first generallycylindrical valving portion for general control by said first valvingportion, second fluid outlet passage means formed in said second housingportion as to communicate with said annular chamber, third fluid outletpassage means formed in said second housing portion as to be generallyjuxtaposed to said second generally cylindrical valving portion forgeneral control by said second valving portion, fourth fluid passagemeans communicating between said first fluid inlet passage means andsaid fluid-flow passage means, wherein when said armature means is movedas to most restrict flow of said fluid medium out of said fluid-flowpassage means the pressure of said fluid medium causes said spool valvemeans to move in a direction whereby said second valving portion atleast further restricts flow of said fluid medium from said annularchamber and through said third fluid outlet passage means toward sumpand said first valving portion reduces its restrictive effect to flow ofsaid fluid medium through said first fluid inlet passage means and intosaid annular chamber and out of said second fluid outlet passage meansto associated structure to be acted upon by said fluid medium, whereinthe diametrical dimension of said first cylindrical valving portion issubstantially different from the diametrical dimension of said secondcylindrical valving portion, and resilient means normally resilientlyurging said spool valve means in a direction generally toward furtherincreasing communication between said annular chamber and said thirdfluid outlet passage means, wherein said field coil means is effectivefor producing a magnetic flux upon application of an electrical currentto said field coil means, wherein when a preselected magnitude ofelectrical current is flowed through said field coil means said armaturemeans is moved as to most restrict flow of said fluid medium out of saidfluid-flow passage means, and wherein said resilient means comprises acoiled compression spring situated in said annular chamber andcircumferentially about said axially extending body means.
 7. A pressureregulating assembly according to claim 6 and further comprising springmeans carried generally within said annular chamber, and wherein saidcoiled compression spring is at one functional end thereof operativelyengaged with said spring perch and at an other functional end thereofoperatively engaged with said second generally cylindrical valvingportion.
 8. A pressure regulating assembly for regulating the pressureof a flowing fluid medium, comprising housing means, said housing meanscomprising a first housing portion and a second housing portion,electrical field coil means carried by said first housing portion, polepiece means situated generally within said field coil means, a valveseat, fluid-flow passage means formed as to be generally circumscribedby said valve seat, said pole piece means comprising a pole piece endface portion, armature means at least partly situated generally withinsaid field coil means, said armature means comprising an armature endface portion, wherein said armature means is situated with respect tosaid pole piece means as to thereby cause said armature end face portionto be juxtaposed to said pole piece end face portion, wherein saidsecond housing portion comprises a generally cylindrical inner chamber,spool valve means situated in said cylindrical inner chamber and movablewith respect to said cylindrical inner chamber and relatively movablewith respect to said armature means, said spool valve means comprisingat least first and second axially aligned cylindrical valving portions,said spool valve means further comprising generally axially extendingbody means situated between and operatively interconnecting said firstand second cylindrical valving portions, said generally axiallyextending body means being relatively small in transverse cross-sectionas to thereby define an annular chamber circumferentially between saidaxially extending body means and said cylindrical inner chamber andaxially confined between said first and second generally cylindricalvalving portions, first fluid inlet passage means formed in said secondhousing portion as to be generally juxtaposed to said first generallycylindrical valving portion for general control by said first valvingportion, second fluid outlet passage means formed in said second housingportion as to communicate with said annular chamber, third fluid outletpassage means formed in said second housing portion as to be generallyjuxtaposed to said second generally cylindrical valving portion forgenerally control by said second valving portion, fourth fluid passagemeans communicating between said first fluid inlet passage means andsaid fluid-flow passage means, wherein when said armature means is movedas to most restrict flow of said fluid medium out of said fluid-flowpassage means the pressure of said fluid medium causes said spool valvemeans to move in a direction whereby said second valving portion atleast further restricts flow of said fluid medium from said annularchamber and through said third fluid outlet passage means toward sumpand said first valving portion reduces its restrictive effect to flow ofsaid fluid medium through said first fluid inlet passage means and intosaid annular chamber and out of said second fluid outlet passage meansto associated structure to be acted upon by said fluid medium, whereinthe diametrical dimension of said first cylindrical valving portion issubstantially different from the diametrical dimension of said secondcylindrical valving portion, and resilient means normally resilientlyurging said spool valve means in a direction generally toward furtherincreasing communication between said annular chamber and said thirdfluid outlet passage means, wherein said field coil means is effectivefor producing a magnetic flux upon application of an electrical currentto said field coil means, wherein when a preselected magnitude ofelectrical current is flowed through said field coil means said armaturemeans is moved as to least restrict flow of said fluid medium out ofsaid fluid-flow passage means, and wherein said resilient meanscomprises a coiled compression spring situated in said annular chamberand circumferentially about said axially extending body means.
 9. Apressure regulating assembly according to claim 8 and further comprisingsecond spring means, said second spring means being operativelyconnected to said armature means as to resiliently urge said armaturemeans to a position as to most restrict flow of said fluid medium out ofsaid fluid-flow passage means.